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      <title>ChannelHandler和Pipeline处理模型 - 交互式测验</title>
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              <h1>ChannelHandler和Pipeline处理模型 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
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      <script>
        const quizData = [
  {
    "question": "在Netty中，`ChannelPipeline` 的主要职责是什么？",
    "options": [
      "直接管理和分配线程资源给不同的Channel。",
      "它是一个`ChannelHandler`的容器，负责管理这些处理器并按顺序组织I/O事件的流转。",
      "负责创建和配置底层的网络连接（Socket）。",
      "作为数据缓存区，临时存储待处理的网络数据包。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "`ChannelPipeline` 扮演着 `ChannelHandler` 链的容器和管理者的角色。它并不直接处理I/O操作或管理线程，而是确保当网络事件发生时，能够按照预定义的顺序流经一系列的处理器（`ChannelHandler`），从而实现对数据处理流程的解耦和复用。",
    "source": "文档中「1. ChannelHandler 和 ChannelPipeline 概述」部分",
    "hint": "文档中提到，Netty 通过一个组件来“管理多个 ChannelHandler”，这个组件是什么？"
  },
  {
    "question": "根据文档中的代码示例，`DefaultChannelPipeline` 的内部结构是怎样的？",
    "options": [
      "一个基于数组的列表，通过索引快速访问处理器。",
      "一个先进先出（FIFO）的队列结构。",
      "一个带有特殊 `head` 和 `tail` 节点的双向链表，用于组织 `ChannelHandler`。",
      "一个使用哈希表（HashMap）存储的键值对集合。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档中的 `DefaultChannelPipeline` 源码片段明确展示了 `head` 和 `tail` 两个 `ChannelHandlerContext` 成员，以及在 `addLast0` 方法中通过 `prev` 和 `next` 指针将新的处理器链接起来的操作。这正是双向链表的典型特征，它使得事件可以在管道中双向传播（入站和出站）。",
    "source": "文档中「2. ChannelPipeline 的结构」部分",
    "hint": "观察 `DefaultChannelPipeline` 的源码，其中的 `head`、`tail`、`next` 和 `prev` 字段揭示了其底层的数据结构。"
  },
  {
    "question": "当一个 `ChannelHandler` 处理完一个入站事件（如读取数据）后，如果希望将该事件继续传递给管道中的下一个处理器，应该调用哪个方法？",
    "options": [
      "调用 `ctx.write(msg)`",
      "直接返回处理后的 `msg` 对象",
      "调用 `ctx.fireChannelRead(msg)`",
      "调用 `pipeline.nextHandler(msg)`"
    ],
    "correctAnswerIndex": 2,
    "explanation": "`fireChannelRead()` 是 `ChannelHandlerContext` 提供的标准方法，用于触发（fire）一个 `channelRead` 事件，并将其沿着 `ChannelPipeline` 传递给下一个 `ChannelInboundHandler`。`ctx.write(msg)` 用于触发一个出站事件。",
    "source": "文档中「5. 入站事件的处理流程」部分",
    "hint": "在处理入站事件的 `MyChannelHandler` 示例代码中，最后一行是如何将消息传递下去的？"
  },
  {
    "question": "根据文档描述，`ChannelHandler` 分为入站处理器和出站处理器。以下哪项是对它们功能的正确描述？",
    "options": [
      "入站处理器负责将数据写入网络，而出站处理器负责从网络读取数据。",
      "入站处理器负责处理从网络接收的事件（如数据读取和解码），而出站处理器负责处理向网络发送的事件（如数据编码和写入）。",
      "入站处理器总是先于出站处理器执行。",
      "入站处理器和出站处理器处理的事件类型完全相同，只是执行顺序不同。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档明确定义了这两类处理器的角色：入站处理器（Inbound）处理的是进入应用的数据流和事件，例如从客户端接收到数据；而出站处理器（Outbound）处理的是从应用发出的数据流和事件，例如向客户端发送响应。它们的方向和功能是相反的。",
    "source": "文档中「3. ChannelHandler 的角色与功能」部分",
    "hint": "思考数据流动的方向：数据是“进来”还是“出去”？"
  },
  {
    "question": "在Netty的事件处理模型中，`ChannelHandlerContext` 的核心作用是什么？",
    "options": [
      "它代表了底层的网络通道（Channel）本身。",
      "它是一个用于存储业务逻辑数据的全局上下文。",
      "它将 `ChannelHandler` 和 `ChannelPipeline` 关联起来，并提供了处理器之间交互和事件传播的能力。",
      "它专门用于处理异常事件，是Netty的异常处理中心。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "`ChannelHandlerContext` 是一个至关重要的中间对象，它既持有与之关联的 `ChannelHandler`，也知道自己在 `ChannelPipeline` 中的位置。它提供了 `fire` 系列方法（用于传播入站事件）和 `write` 等方法（用于传播出站事件），从而构成了Netty事件流的核心驱动机制。",
    "source": "文档中「4. ChannelHandlerContext 和事件传递机制」部分",
    "hint": "文档中提到，通过这个对象，“ChannelHandler 可以访问通道、管道中的其他处理器，或者向后传递事件”。"
  },
  {
    "question": "假设一个 `ChannelPipeline` 中依次添加了 HandlerA (Inbound), HandlerB (Outbound), HandlerC (Inbound)。当一个入站事件发生时，正确的处理顺序是怎样的？",
    "options": [
      "HandlerA -> HandlerC",
      "HandlerA -> HandlerB -> HandlerC",
      "HandlerC -> HandlerA",
      "HandlerA -> HandlerC -> HandlerB"
    ],
    "correctAnswerIndex": 0,
    "explanation": "入站事件在 `ChannelPipeline` 中从 `head` 向 `tail` 方向传播，并且只会流经 `ChannelInboundHandler` 类型的处理器。因此，事件会先到达 HandlerA，处理后如果继续传播，会跳过类型不匹配的 HandlerB (Outbound)，直接到达 HandlerC。",
    "source": "文档中「5. 入站事件的处理流程」和「7. 管道的生命周期和事件流」部分",
    "hint": "入站事件和出站事件有各自的传播路径，它们会跳过类型不匹配的处理器。"
  },
  {
    "question": "在一个出站处理器 `MyOutboundHandler` 的 `write` 方法中调用 `ctx.write(msg, promise)`，这个操作的含义是什么？",
    "options": [
      "将数据直接写入操作系统的网络缓冲区，完成发送。",
      "这是一个递归调用，会导致无限循环。",
      "将写事件和数据传递给 `ChannelPipeline` 中的前一个（更靠近 `tail` 的）出站处理器继续处理。",
      "将消息重新作为入站事件，从管道的头部开始处理。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "出站事件的传播方向是从 `tail` 向 `head`。当在一个 `ChannelOutboundHandler` 的 `write` 方法中调用 `ctx.write()` 时，实际上是将该写事件传递给它在管道中的前一个 `ChannelOutboundHandler` 进行处理。这个过程会一直持续，直到事件到达 `head` 节点，最终由Netty的底层机制写入Socket。",
    "source": "文档中「6. 出站事件的处理流程」部分",
    "hint": "出站事件的流动方向与入站事件相反。思考一下，在链表中，“继续传递”意味着走向哪个方向？"
  }
];
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                '<h3>得分</h3>' +
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                '<div class="score-card">' +
                '<h3>正确率</h3>' +
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                '<div class="score-card">' +
                '<h3>错误率</h3>' +
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                '<div class="score-card score-details">' +
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                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  